The present invention relates generally to containers in the form of flexible bags having an open end with a releasable closure, and is particularly concerned with canister bags suitable for holding various household products such as flour, sugar, cake mixes, and the like, as well as for bags for storage and disposal of waste products.
Various household products for cooking and the like are conventionally sealed in a flexible bag which may be placed in an outer cardboard container. Such bags can often not be re-sealed after opening, making it difficult to keep the product fresh and in good condition when the entire contents of the bag are not used at one time. Also, dispensing a measured quantity of product from such bags can be a problem, and spills are a common occurrence.
Another application for flexible bag-like containers is for collection, storage and disposal of body fluids such as urine, blood, vomit, or the like. Such containers are often used when a person is at a location where no convenient bathroom facilities are available, such as while traveling, camping, on outdoor construction sites, or at other outdoor events. A fluid containment bag for this purpose is described, for example, in U.S. Pat. No. 5,116,139 of Young et al. and in application Ser. No. 09/206,616 of Young et al. filed Dec. 7, 1998, now abandoned. It can sometimes be difficult to hold such bags open during use, and it is important that they can be completely sealed to hold the waste products after use.
It is an object of the present invention to provide a new and improved canister bag suitable for various uses, as well as a new and improved method of manufacturing such a bag.
According to one aspect of the present invention, a lock top canister bag is provided, which comprises a bag of flexible material having a closed end and an open end, and a closure device secured to the open end of the bag for releasably closing the open end, the closure device comprising a pair of opposing flat strips of stiffer material than the bag extending from the open end of the bag, the strips having a lower edge secured to the open end of the bag, an upper edge, and opposite ends, and the strips being joined together at least at one of their ends, and a handle flap extending upwardly from the upper edge of the strips at least at one end of the strips, the handle flap being integrally formed with the strips and having a fold line joining the handle flap to the strips, whereby the bag opening can be reshaped and stabilized by folding the flap downward. This action produces dynamic tensional or hoop stress thereby locking the bag in the open position.
The closure device may comprise opposing zip lock type fastener formations formed in opposing inner portions of the strips. The bag is opened by releasing the closure device, and can be held manually in an open condition by urging opposite ends of the strips towards one another, such that the strips each flex outwardly. If desired, the handle flap can then be bent downwardly outside the strips about the fold line in order to hold the bag in an open condition, without requiring the user to manually hold it open. Upwardly projecting flaps or tabs may be provided at both ends of the bag opening, secured to the remainder of the strips along fold lines. In this case, both flaps may be folded downward through at least 90 degrees, providing dynamic tensioning or hoop stress to lock the bag in an open condition. This can be useful both when the bag contains products to be dispensed, such as cooking or other household products, and when the bag is used for waste disposal.
The handle flap may be designed as a pour spout to allow products to be poured from the bag. A handle flap or tab may be provided at one or both ends of the strips, as noted above. The strips, closure device, and handle flap are preferably formed integrally from one or two extruded ribbons of semi-rigid plastic material which are heat sealed to the open top of a bag.
The bag may have an inwardly folded gusset at its lower end which can be flattened to expand and flatten the lower end of the bag so that it can stand in an open condition on a kitchen counter or the like. If the handle flap is bent downwardly to lock the upper end of the bag open, the user does not have to use either hand to hold the bag open, and can readily spoon or scoop product from the bag while cooking or preparing food, for example.
According to another aspect of the present invention, a method of manufacturing lock-top canister bags is provided, which comprises the steps of:
extruding continuous dual parallel ribbons of semi-rigid plastic material having upper and lower edges and opposite side faces, with a zip-lock type fastener channel extending along each inside face, and a fold line spaced above each zip-lock type fastener;
die cutting of the upper edges of the extruded ribbons to form a series of indents extending through the fold lines separated by projecting flaps incorporating uncut portions of the fold lines;
welding the lower edges of the ribbons to the respective upper edges of continuous flexible film sheeting suitable for conversation to bag-like containers; and
cutting and sealing the resulting construct into individual bag-like containers having seals on opposing sides which run perpendicular to the extruded ribbon top and a seal or fold line off the edge opposite the zip-lock type closure.
The die cutting step may use segmented perforation blades in order to provide lines of perforations defining the indents, with the portion of each strip above the lines of perforations forming a removable tear-off portion for later removal by a user. In this case, the upper edges of the two opposing ribbons may be sealed for tamper protection. This will provide evidence of any tampering. Alternatively, the die cutting may be performed by a continuous cutting blade so that the upper portions of the strips are removed prior to final assembly of the bag.
In an alternative method, rather than extruding two parallel ribbons, a single ribbon may be extruded or injection molded with a pair of spaced, parallel zip-lock type fastener channels on one, inner face on opposite sides of a center line, and a pair of parallel fold lines each positioned between a respective zip-lock fastener and the center line. The strip is then folded about the center line with the zip-lock fastener channels facing inwardly and aligned. The opposing halves of the strip may then be die cut with lines of perforations to define portions to be removed later. The edges of the folded strip can then be welded to flexible film sheeting and the resultant structure can be cut and heat sealed to form individual bags.
Where the container is for storing and dispensing household products or the like, the lower end of the bag is preferably formed with an inwardly folded gusset which can be flattened to form a support surface for holding the bag upright on a flat surface. If the container is for use in waste disposal, such as urine disposal, the lower end may be a straight sealed edge. In this case, the bag is preferably also formed with an internal funnel secured to the open end of the bag and extending inwardly into the bag, for conducting fluid from the open end of the bag into the bag. A gellable hydrophilic material is preferably also provided in the bag in this version, for absorbing fluids deposited in the bag.
The bag-like container of this invention has a strip around its open end which incorporates a closure for the bag, a stiffener which provides dynamic tensioning or hoop stress when the handle flap or tab is folded at least 90 degrees away from its original plane. The handle flap can be bent outwardly to function as a handle which can be gripped at a location spaced from the bag opening, and can be bent down to lock the bag open so it does not snap closed if accidentally released. The ability to lock the bag open allows products to be dispensed from the bag without requiring use of either hand to actually hold the bag open. The container is easy and inexpensive to manufacture, and the strip may be secured to any type of bag.